org.apache.myfaces.shared_tomahawk.resource.ResourceLoaderUtils Maven / Gradle / Ivy

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JSF components and utilities that can be used with any JSF implementation. This library is based on the JSF1.1 version of Tomahawk, but with minor source code and build changes to take advantage of JSF2.1 features. A JSF2.1 implementation is required to use this version of the Tomahawk library.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.myfaces.shared_tomahawk.resource;

import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

public class ResourceLoaderUtils
{
    // TODO: In tomcat and jetty it is implemented a Flyweight pattern when converting
    // date headers. For now it is better keep this stuff simple.
    private static final String HTTP_RESPONSE_DATE_HEADER =
        "EEE, dd MMM yyyy HH:mm:ss zzz";
    
    private static final String[] HTTP_REQUEST_DATE_HEADER = {
            "EEE, dd MMM yyyy HH:mm:ss zzz", "EEEEEE, dd-MMM-yy HH:mm:ss zzz",
            "EEE MMMM d HH:mm:ss yyyy" };
    
    private static final TimeZone GMT = TimeZone.getTimeZone("GMT");

    public static String formatDateHeader(long value)
    {
        SimpleDateFormat format = new SimpleDateFormat(
                HTTP_RESPONSE_DATE_HEADER,
                Locale.US);
        format.setTimeZone(GMT);
        return format.format(new Date(value));
    }
    
    public static Long parseDateHeader(String value)
    {
        Date date = null;
        for (int i = 0; (date == null) && (i < HTTP_REQUEST_DATE_HEADER.length); i++)
        {
            try
            {
                SimpleDateFormat format = new SimpleDateFormat(
                        HTTP_REQUEST_DATE_HEADER[i], Locale.US);
                format.setTimeZone(GMT);
                date = format.parse(value);
            }
            catch (ParseException e)
            {
                // all fine
            }
        }
        if (date == null)
        {
            return null;
        }
        return new Long(date.getTime());
    }
    
    //Taken from trinidad URLUtils
    public static long getResourceLastModified(URL url) throws IOException
    {
        if ("file".equals(url.getProtocol()))
        {
            String externalForm = url.toExternalForm();
            // Remove the "file:"
            File file = new File(externalForm.substring(5));

            return file.lastModified();
        }
        else
        {
            return getResourceLastModified(url.openConnection());
        }
    }

    //Taken from trinidad URLUtils
    public static long getResourceLastModified(URLConnection connection) throws IOException
    {
        long modified;
        if (connection instanceof JarURLConnection)
        {
            // The following hack is required to work-around a JDK bug.
            // getLastModified() on a JAR entry URL delegates to the actual JAR file
            // rather than the JAR entry.
            // This opens internally, and does not close, an input stream to the JAR
            // file.
            // In turn, you cannot close it by yourself, because it's internal.
            // The work-around is to get the modification date of the JAR file
            // manually,
            // and then close that connection again.

            URL jarFileUrl = ((JarURLConnection) connection).getJarFileURL();
            URLConnection jarFileConnection = jarFileUrl.openConnection();

            try
            {
                modified = jarFileConnection.getLastModified();
            }
            finally
            {
                try
                {
                    jarFileConnection.getInputStream().close();
                }
                catch (Exception exception)
                {
                    // Ignored
                }
            }
        }
        else
        {
            modified = connection.getLastModified();
        }

        return modified;
    }
}